good good study, day day up!

vendor/gopl.io/ch3/printints/main.go

@@ -0,0 +1,33 @@
+// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+
+// See page 74.
+
+// Printints demonstrates the use of bytes.Buffer to format a string.
+package main
+
+import (
+	"bytes"
+	"fmt"
+)
+
+//!+
+// intsToString is like fmt.Sprint(values) but adds commas.
+func intsToString(values []int) string {
+	var buf bytes.Buffer
+	buf.WriteByte('[')
+	for i, v := range values {
+		if i > 0 {
+			buf.WriteString(", ")
+		}
+		fmt.Fprintf(&buf, "%d", v)
+	}
+	buf.WriteByte(']')
+	return buf.String()
+}
+
+func main() {
+	fmt.Println(intsToString([]int{1, 2, 3})) // "[1, 2, 3]"
+}
+
+//!-